Ultraviolet irradiation apparatuses have hitherto been used for general purposes, including fluorescence reaction observations in the fields of medicine, biotechnology, and so forth, disinfection, the adhesion of electronic components, and the curing of an ultraviolet curable resin and ink. In particular, a high-pressure mercury lamp, a metal halide lamp, or the like is used as a lamp light source of an ultraviolet irradiation apparatus for use in the curing of an ultraviolet curable resin used for the adhesion of a miniaturized component in the field of electronic components, the curing of an ultraviolet curable ink used in the field of printing, or like purposes.
In recent years, from the viewpoint of lessening the burden on the environment, an ultraviolet light-emitting element has been adopted for use as a lamp light source because of its longer service life, greater energy efficiency, and capability of suppression of ozone generation.
An ultraviolet light-emitting element has a relatively low irradiance, and therefore, for example, as described in Japanese Unexamined Patent Publication JP-A 2003-124528, a device constructed by mounting a plurality of light-emitting elements on a single substrate is commonly used. Thus, ultraviolet irradiation energy required for curing an ultraviolet curable ink can be secured.
In such a device, however, although it is possible to secure the ultraviolet irradiation energy for irradiation in terms of integrated quantity, the intensity of ultraviolet irradiation per unit area is not high, which may cause insufficient curing.